It's not uncommon for some workloads to do a bunch of I/O to a file and
delete it just afterward. If knfsd has a cached open file however, then
the file may still be open when the dentry is unlinked. If the
underlying filesystem is nfs, then that could trigger it to do a
sillyrename.
On a REMOVE or RENAME scan the nfsd_file cache for open files that
correspond to the inode, and proactively unhash and put their
references. This should prevent any delete-on-last-close activity from
occurring, solely due to knfsd's open file cache.
Signed-off-by: Jeff Layton <jeff.layton@xxxxxxxxxxxxxxx>
---
fs/nfsd/filecache.c | 27 +++++++++++++++++++++++++++
fs/nfsd/filecache.h | 1 +
fs/nfsd/trace.h | 17 +++++++++++++++++
fs/nfsd/vfs.c | 23 +++++++++++++++++++++--
4 files changed, 66 insertions(+), 2 deletions(-)
diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c
index 44dee985864b..a114f3a69117 100644
--- a/fs/nfsd/filecache.c
+++ b/fs/nfsd/filecache.c
@@ -272,6 +272,33 @@ nfsd_file_find_locked(struct knfsd_fh *fh, unsigned int may_flags,
return NULL;
}
+/**
+ * nfsd_file_force_close - attempt to forcibly close a nfsd_file
+ * @fh: filehandle of the file to attempt to remove
+ *
+ * Walk the whole hash bucket, looking for any files that correspond to "fh".
+ * If any do, then unhash them and put the hashtable reference to them.
+ */
+void
+nfsd_file_close_fh(struct knfsd_fh *fh)
+{
+ struct nfsd_file *nf;
+ struct hlist_node *tmp;
+ unsigned int hashval = file_hashval(fh);
+ LIST_HEAD(dispose);
+
+ spin_lock(&nfsd_file_hashtbl[hashval].nfb_lock);
+ hlist_for_each_entry_safe(nf, tmp, &nfsd_file_hashtbl[hashval].nfb_head, nf_node) {
+ if (fh_match(&nf->nf_handle, fh)) {
+ nfsd_file_unhash(nf);
+ nfsd_file_put_locked(nf, &dispose);
+ }
+ }
+ spin_unlock(&nfsd_file_hashtbl[hashval].nfb_lock);
+ trace_nfsd_file_close_fh(hashval, fh, !list_empty(&dispose));
+ nfsd_file_dispose_list(&dispose);
+}
+
__be32
nfsd_file_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp,
unsigned int may_flags, struct nfsd_file **pnf)
diff --git a/fs/nfsd/filecache.h b/fs/nfsd/filecache.h
index b8a59d615729..40c47cac2c33 100644
--- a/fs/nfsd/filecache.h
+++ b/fs/nfsd/filecache.h
@@ -44,6 +44,7 @@ int nfsd_file_cache_init(void);
void nfsd_file_cache_purge(void);
void nfsd_file_cache_shutdown(void);
void nfsd_file_put(struct nfsd_file *nf);
+void nfsd_file_close_fh(struct knfsd_fh *fh);
__be32 nfsd_file_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp,
unsigned int may_flags, struct nfsd_file **nfp);
#endif /* _FS_NFSD_FILECACHE_H */
diff --git a/fs/nfsd/trace.h b/fs/nfsd/trace.h
index ff26d91f8106..c45d318e3a0b 100644
--- a/fs/nfsd/trace.h
+++ b/fs/nfsd/trace.h
@@ -147,6 +147,23 @@ TRACE_EVENT(nfsd_file_acquire,
show_nf_may(__entry->nf_may), __entry->nf_time,
__entry->nf_file, be32_to_cpu(__entry->status))
);
+
+TRACE_EVENT(nfsd_file_close_fh,
+ TP_PROTO(unsigned int hash, struct knfsd_fh *handle, int found),
+ TP_ARGS(hash, handle, found),
+ TP_STRUCT__entry(
+ __field(unsigned int, hash)
+ __field_struct(struct knfsd_fh, handle)
+ __field(int, found)
+ ),
+ TP_fast_assign(
+ __entry->hash = hash;
+ __entry->handle = *handle;
+ __entry->found = found;
+ ),
+ TP_printk("hash=0x%x handle=%s found=%d", __entry->hash,
+ show_nf_fh(__entry->handle), __entry->found)
+);
#endif /* _NFSD_TRACE_H */
#undef TRACE_INCLUDE_PATH
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 8308d786c1e2..c70c6fbec4d7 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -1581,6 +1581,21 @@ out_nfserr:
goto out_unlock;
}
+static __be32
+nfsd_close_cached_files(struct dentry *dentry, struct svc_fh *fhp)
+{
+ __be32 err = nfs_ok;
+ struct knfsd_fh kfh = { 0 };
+
+ if (d_really_is_positive(dentry) && S_ISREG(d_inode(dentry)->i_mode)) {
+ err = fh_compose_shallow(&kfh, fhp->fh_maxsize,
+ fhp->fh_export, dentry, fhp);
+ if (err == nfs_ok)
+ nfsd_file_close_fh(&kfh);
+ }
+ return err;
+}
+
/*
* Rename a file
* N.B. After this call _both_ ffhp and tfhp need an fh_put
@@ -1650,6 +1665,7 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen,
if (ffhp->fh_export->ex_path.dentry != tfhp->fh_export->ex_path.dentry)
goto out_dput_new;
+ nfsd_close_cached_files(ndentry, tfhp);
host_err = vfs_rename(fdir, odentry, tdir, ndentry, NULL, 0);
if (!host_err) {
host_err = commit_metadata(tfhp);
@@ -1719,10 +1735,13 @@ nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
if (!type)
type = d_inode(rdentry)->i_mode & S_IFMT;
- if (type != S_IFDIR)
+ if (type != S_IFDIR) {
+ nfsd_close_cached_files(rdentry, fhp);
host_err = vfs_unlink(dirp, rdentry, NULL);
- else
+ } else {
host_err = vfs_rmdir(dirp, rdentry);
+ }
+
if (!host_err)
host_err = commit_metadata(fhp);
dput(rdentry);
--
2.4.3
--
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